Flexible curtain structure

ABSTRACT

There is provided an improved structure for a flexible curtain and closure including the same which is characterized by a butt joint between panels, which joint is reinforced by at least one overlaid reinforcing strap.

United States Patent Wilbur R. Youngs;

James G. Hugus, both of Findlay, Ohio 813,160

Apr. 3, 1969 June 8, 1971 Closures, lac.

Inventors Appl. No. Filed Patented Assignee FLEXIBLE CURTAIN STRUCTURE 7 Claims, 4 Drawing Figs.

U.S. Cl 160/264, 160/243,160/310 Int. Cl A47g 5/02 Field of Search 160/242,

[56] References Cited UNITED STATES PATENTS 2,890,747 6/1959 Mur hy 160/368 G 3,031,359 4/1962 Blank etal..... 161/38 3,321,781 5/1967 Reich 161/38 3,460,602 8/1969 Hugus 160/310 X 3,475,260 10/1969 Stokes Primary Examiner--Peter M. Caun Attorney-McNenny, Farrington, Pearne and Gordon ABSTRACT: There is provided an improved structure for a flexible curtain and closure including the same which is characterized by a butt joint between panels, which joint is reinforced by at least one overlaid reinforcing strap.

PATENTEU JUN 8 lSYl r2 20 mm. 0 0 38 l I I 1 I l l i l I l l I l I lllll INVENTORS:

W/L BUR R YOU/V65 JAMES 6. H0605 (PRIOR ART) ATTORNEYS BY MCNenm Fdmngfon, Pedme Gordon FLEXIBLE CURTAIN STRUCTURE BACKGROUND OF INVENTION This invention relates as indicated to a flexible curtain structure and more particularly to a flexible curtain structure which is adapted to close a relatively large opening, for example an airplane hangar door, a gymnasium divider, or a garage door structure. The magnitude of these openings is such as to require the piecing together of panels of flexible curtain material to form a curtain of sufficient dimension to cover the opening. The joinder of individual panels of material for use for the purposes above-mentioned has prior to this time normally been accomplished by a simple lap joint in which a marginal portion of one panel is simply lapped over a marginal portion of an adjacent panel, and the two panels secured together by any suitable means. This procedure while convenient has introduced difficulties particularly in connection with curtains which are supported on a roller mounted adjacent the upper marginal edge or head member of the openmg.

it has been pointed out in my copending application Ser. No. 561,627, now U.S. Pat. No. 3,421,568 dated .Ian. 14, 1969, that rollers which span openings of such great widths undergo sagging when supported only at the extremities thereof, and accordingly it is necessary to provide at spaced intermediate intervals support members for the roller. These support rollers are so constructed and disposed as to allow the main curtain roller to rotate about its axis for rolling and unrolling the curtain to raise and lower the curtain. The curtain material is wound on the main roller and is disposed between the main roller body and the support rollers. Suitable allowance is made for the increase in thickness or apparent diameter of the main roller as the material is wound upon it and for decrease in the apparent diameter of the roller as the material is unwound therefrom to close the opening. These considerations form no part of the present invention except that the present invention is compatible for use in such structures. The disclosure of my aforesaid prior patent is incorporated herein in its entirety by reference thereto for a fuller understanding of an environment in which the present invention may be utilized.

As pointed out in my prior application, when a reinforced thermoplastic material, for example, nylon cord reinforced polyvinyl chloride film, is used in fabricating the flexible curtain member, and that member is exposed to pressure between the supporting rolls and the main roller, it is squeezed between the rollers and thus extended in length in this portion. ln a long curtain, the extension due to the application of compressive force in a localized region will cause the curtain to roll unevenly, and unsightly puckering as well as undue wear on the curtain material itself will be experienced. This problem can be overcome as described in such prior application by supplying at these points diameter-increasing means so that the effective diameter of the roll as the material is wrapped thereon is larger by an amount sufficient to account for the increase in length of the material brought about by squeezing the material between the support rolls and the main roller. This can be done in two ways. The diameter of the roll can be enlarged by fabricating portions of increased diameter into the roller body itself at intervals which correspond to those regions where the support rollers will be mounted in the final assembly. Alternatively, the thickness of the curtain material itself can be used to achieve the same result in substantially the same way by providing a multiple thickness of the curtain, for example, in the region where the curtain will pass under compression between the support roller and the main curtain roller. As the extra thickness of curtain material is wound about the roller, the rate of increase of the apparent diameter of the roller with the material wrapped therearound is sufficient to offset the increase in length occurring in the nip between the main roller and the support rollers and hence puckering and undue wear are avoided.

As indicated above, a common procedure for joining adjacent panels of flexible curtain material has heretofore been a lap joint. With the nylon cord reinforced poly(vinyl chloride) type film, the seal is effected by means of heat, and the technique of heat sealing" adjacent panels in a lap joint is a well known commercial procedure for fabricating large area panels from a plurality of smaller panels. The advantages of the prior invention were achieved by locating the support members for the main roll at the lapped joints in the fabricated curtain body. The added thickness achieved the intended obje'ctives of the aforesaid invention.

The present invention represents a substantial improvement in the structure of flexible curtains which are adapted for use with so-called "fixed roll" closure devices. According to the present invention, instead of a lap joint, a butt joint between adjacent panels is effected, which butt joint is reinforced by at least one strip of material separately cut and applied along the butt joint portion and extending laterally therefrom into sealing engagement with adjacent marginal portions of the adjacent panels. The lapping material for the butt joint is preferably of the same chemical composition as the curtain membrane itself. It is not necessarily of the same thickness as the curtain membrane itself.

In the lap joint structure of the prior art, control could not easily be exercised upon the thickness of the lap, and very frequently there was encountered in the formation of the lap joint a buildup of a ridge along each of the marginal edges of the heat sealing element because of the expelling of excess molten plastic from under the edges of the heated bars which are commercially used in forming the seal. This socalled side squirt" is eliminated in the present structure, and this is a very desirable advantage of the present invention. Such "side squirt ridges also contribute to uneven rolling in the structures described in my above-mentioned patent application. Thus, whereas the lap joint offered no ability to control the extent of buildup for diameter increasing purposes along a seam, the present structure permits the use of a thicker lapping member for the butt joint, thereby enabling better control of the amount of buildup necessary to accommodate stretching or lengthening of the curtain material as it passes onto the takeup roller, or main roller, in the region of a support member. In a strip-reinforced butt joint of the type herein described, "side squirt" is virtually nonexistent.

Another problem which is greatly alleviated is the problem of differential relaxation" between material which is part of the prior lap joint and the adjacent unlapped membrane material. Because of the fusionof the two marginal edges in lapped relation to form the prior seams, the relaxation characteristics of the plastic membrane are altered from one another in this region giving rise to differential relaxation." This effect was found to contribute to puckering in the flexible eurtain member. Also because of the differential relaxation factor in the lap-type joint, there was observed a measurable reduction in the overall length of the heat-sealed seam portion as compared with the immediately adjacent length of the material. This resulted in a sc'alloped" effect along the lower marginal edge of the flexible curtain. This increases handling problems and also tends to promote puckering. With the reinforced butt joint of the present invention, better seam control is experienced and this problem is substantially eliminated.

Still another highly important problem is overcome with the structures of the present invention as compared with the prior art. It has now been discovered that improved results are obtained in the performance of the curtain through many cycles of opening and closing a hangar door or a garage door or a room divider, if tension is applied to the curtain from side to side. This tension is of a substantial magnitude applied laterally in a direction parallel to the axis of the main curtain roller and may be sufficient to stretch a 9-foot panel of nylon cord-reinforced vinyl plastic film as much as one-half inch. Such lateral tension contributes to more even rolling of the membrane and greatly improves the appearance of a large hangar door panel, for example. With the lap-type joint, such lateral tensioning, when it is used, causes the lap joint to become slightly cocked or displaced out of the plane of the panel. Thus there is again introduced an imbalance on the seam portion itself which results in uneven rolling of the curtain, unsightly puckering and again undue wear. With the reinforced butt joint structure of the present invention, the curtain may be placed under lateral tension without experiencing cocking in the region of the seam or joinder between adjacent panels and thus the difficulties attendant such cocking are avoided.

The present invention may be better understood by having reference to the annexed drawings which are illustrative of a preferred embodiment of the present invention and showing an environment in which it issued, and wherein:

FIG. 1 is an illustration in .plan view ofa flexible curtain embodying the principles of the present invention supported from a fixed roller" and shown in the closed position.

FIG. 2 is a fragmentary prospective illustration of one end of a main roller with flexible curtain material partially wrapped therearound and showing the counterwinding of Iongitudinal curtain tensioning means for the flexible curtain member.

FIG. 3 is a cross-sectional view of a fiber reinforced flexible curtain member as it appears across a butt joint having a reinforcing strip coacting therewith and as the structure appears in the plane indicated by 33 in FIG. 1.

FIG. 4 is an illustration of the prior art lapjoint.

BRIEF STATEMENT OF INVENTION Briefly stated, the present invention is in a flexible rectangular curtain structure comprising a plurality of panels of flexible material and rectangular configuration in side-by-side relation and having adjacently disposedmarginal edges in coplanar, parallel confronting relation; and a separate narrow strip of flexible material of like chemical nature adhering to each of adjacent panels in overlapping relation with marginal portions of each of said adjacent panels and coextensively overlying said confronting marginal edges. In more specific embodiments of this invention, the flexible curtain structure is formed from an impervious material which is a heat scalable thermoplastic resin, and still more preferably one which is reinforced with nylon strands or cords forming a woven matrix for the vinyl resin.

DETAILED DESCRIPTION OF DRAWINGS Referring now more particularly to FIG. I, there is here represented an environmental installation of a flexible curtain embodying the present invention. The surface represents a portion of the forward wall of a building structure, such as an airplane hangar, having an opening 12 therein dimensioned to permit passage of aircraft. The opening I2 is rectangular and is divided by parallel vertical side members 14 and 16 and a top horizontal margin 18 which is parallel to the ground level or floor of the building as the case may be. The closure device for the opening 12 includes a main roller 20 having its lefthand extremity 22 supported by suitable bearing means 24 which are in turn secured to header 26 above the opening. In like manner, the right-hand extremity 28 is also joumaled for rotation in bearing assembly 30 which is likewise secured to header 26. The ends of the roller 20 are therefore securely mounted on the building structure. The right-hand extremity in the embodiment shown is also provided with drive means including an electric motor 32 having a drive gear 34 engaging driven gear 36. Any suitable drive means may be provided to impart positive rotational torque to one or both extremities of roller 20. For example, instead ofa gear drive means, chain or belt drive means may be employed.

Because roller 20 is a very long roller, for example 60 to 240 feet in length, a relatively small diameter roll, e.g. 4 inches to 8 inches in diameter, would, unless supported, sag intermediate fixed support extremities such as bearings 24 and 30. To prevent roller sag, support brackets 38 and 40 are provided,

the details of which are clearly illustrated in U.S. Pat. No. 3,421,568. These support brackets 38 and 40 are secured to the building structure 10 and support for rotation therein one or more support rollers 42 or 44. Brackets 38 and 40 extend outwardly from the building structure 10 over the top of the roller 20 downwardly to a position below the roller 20 and then inwardly to support the support rollers 42 and 44. There is provided also a flexible curtain 46 which is rectangular in shape and dimensioned to cover the opening 12 and desirably to extend slightly beyond the marginal edges 14, I6, and 18 to provide adequate closure thereof. Flexible curtain 46 is secured along its top marginal edge to the roller 20 by any suitable means. In the affixing of the curtain 46 to the roller, tension may be applied to the curtain by stretching the curtain as it is secured to the roller. This tensioning force is in a direction axial of the roller. It is a lateral tensioning of the curtain and improves the performance of the curtain. This is an optional feature and not a mandatory installation technique. Along the bottom marginal edge 48 there is provided a bottom rail 50 which is desirably a relatively heavy unit extending along the bottom marginal edge or free marginal edge 48 of curtain 46. The side marginal edges of curtain 46 are contained within channels 52 and 54 which serve to guide the bottom rail 50 as it moves from the fully open position at the top to the closed position shown in FIG. 1 at the bottom. Tensioning means including side cables 56 and 58 are conveniently provided, and the details of one form of such tensioning means are clearly set forth in the patent to Hugus issued on Ser. No. 645,856 filed June 8, 1967, now U.S. Pat. No. 3,460,602 dated Aug. 12, 1969.

The structure of the roller itself, the structure of the drive means, the structure of the bearings 24 and 30, the structure of the tensioning mechanism, the structure of the side channels 52 and 54 and the structure of bottom rail 50 form no part of the present invention and are described merely to set one environment in which the present invention is utilized.

As indicated above, the present invention is in the structure of curtain 46. The material from which the curtain 46 is fabricated is not critical, but the best embodiments of the present invention utilize flexible curtains which are built up from rectangular panels which are sealed together to form the complete curtain. A most satisfactory material for this purpose is a nylon cord-reinforced poly(vinyl chloride) sheet. The nylon cord is woven into a wide mesh matrix, and the vinyl resin cast about the matrix substantially as represented in FIGS. 3 and 4. This material is well known and is commercially available, and its precise composition and structure also form no part of the present invention.

FIG. 4 shows the manner by which the prior art joined adjacent panels together to form large panels utilizing a lap joint in which panel A is heat sealed to panel B along a marginal portion thereof. The heat required to fuse the panels A and B at their juncture is supplied from a long narrow heating bar which is brought into pressure contact along the lapped marginal portions of sheets A and B. This mode of forming the seal results in the development of longitudinally extending ridges 60 and 62 as a result ofside squirt."

In accordance with the present invention, two panels C and D have their confronting marginal edges 64 and 66 brought into juxtaposition to form a butt joint therebetween. A reinforcing strip E is provided which overlaps the juncture 68 between the abutting panels C and D and extends laterally to cover the marginal portions 70 and 72 of the respective panels C and D. Strip E is a separate strip and its thickness need not be the same as the thickness of panels C and D. In the case of the prior art structure, the thickness of panel A and the thickness of panel B are necessarily the same. Thus, under manufacturing conditions, the thickness of the lap joint of the prior art is a predetermined fixed value dependent solely upon the thicknesses of the joining panels A and B. In the present case, however, while the thickness of panel C and I) is identical, the thickness of the separate strip E may be the same as the thickness of panels C and D or it may be different. Thus,

the strip E may be utilized to compensate for the stretching that the curtain undergoes when it passes between support roller 42 and main roller (FIG. I).

The seal is effected in a most similar manner to that used in the prior art except that the width of the heating bar may exceed the width of strip E. The temperature for effecting a heat seal" is the same, and all other conditions are essentially the same for effecting a heat seal as is well known to those skilled in the art of fabricating large panels of this type. However, in the improved device of the present invention, the formation of ridges such as ridges 60 and 62 may be conveniently avoided.

It can also be observed when comparing the structures of FIGS. 3 and 4 that the imposition of tension forces across the juncture of the adjacent panels A and B in the case of the prior art and, panels C and D in FIG. 4, that a force couple is set up in the case of FIG. 4 tending to twist the joint out of the plane of the panel, Le. a cocking effect". In the case of the structure of FIG. 3, this'does not occur when the joint 68 is placed under tension and there is no tendency to displace the joint between strip E and adjacent panels C and D out of the plane of the panel.

It has been also found most desirable to apply a marginal strip such as strip E along each of the free side edges of curtain 46 as shown in FIGS. 1 and 2 although this is not essential to satisfactory operation of the device.

In the device shown in FIG. I, only three panels have been shown in sealed relation to fabricate a curtain large enough to cover the opening 12. Many more such panels may, of course, be used as desired.

In actual use in the environment shown and described with respect to FIG. 1, the support strip E serves to impart at least two functions; namely, reinforcing the butt joint between panels C and D, for example, and the panels D and F (FIG. I). The sealing strip E also provides for the necessary buildup to compensate for stretching in the curtain 46 brought about by its passage between the support roller 42 and the main roller 20, and its passage between the support roller 44 and the main roller 20. The extra thickness of material in this region increases the effective diameter of main roller 20 as material continues to be wound thereupon in this localized region thereby compensating for the lengthening of the curtain 46 due to its passage under pressure between the support rollers 42 and 44, for example, and the main roller 20 with the material of curtain 46 wrapped therearound. The net result is that the curtain in all positions is substantially free of puckering and wrinkling and provides a very neat appearing closure for an opening such as opening 12.

While the invention is particularly useful in connection with plastic curtain materials which are not dimensionally stable under rolling pressure as described above, it is nevertheless applicable to dimensionally stable plastic films whether reinforced or not, particularly when those films are to be placed under lateral tension as would occur when the curtain is stretched in an axial direction as it is applied to the roller 20 and stretched in an axial direction as the bottom rail 50 is attached to the bottom free marginal edge 48 of curtain 46. Even dimensionally stable materials will undergo the cocking effect described in connection with the structure shown in FIG. 4.

There has thus been provided an improved structure for a 6 flexible curtain fabricated from a plurality of panels having dimensions less than the dimensions of the opening. which panels are joined together along marginal edges thereof, and which joinders are characterized .by a butt type'of joint reinforced with an overlying strip which covers the joint itself and extends laterally into the marginal portions of the adjacent panels. This structure obviates'numerous difficulties encountered with the prior art lap-type joint for structures which are utilized in an environment such as that shown in FIG. 1.

What we claim is:

1. A closure apparatus for an opening in a building structure, said opening being defined by a base, a head member and side members, comprising: f

a. an elongated roller of sufficient length to sag when supported in a horizontal position by its extremities only;

b. means for securing the ends of the roller to said header adjacent the opening for rotation about its longitudinal axis;

c. a flexible rectangular curtain dimensioned to cover the opening and secured along a marginal edge to said elongated roller and fabricated from:

I. a plurality of panels of flexible material and rectangular configuration in coplanar side-by-side relation and having adjacently disposed marginal edges in confronting relation; and

2. a separate narrow strip of flexible material similar to said panel material secured to each of adjacent panels in overlapping relation with marginal portions of each of said adjacent panels and coextensively overlying said confronting marginal edges;

e. means for supporting the roller intermediate its extremities including at least one support roller disposed in load supporting relation with said elongated roller and curtain and having its axis of rotation parallel to the axis of rotation of said elongated roller, and a supporting bracket in which said support roller is mounted for rotation, said bracket being secured to said head member and disposed relative to said curtain so that said narrow strip of flexible material passes between said support roller and said elongated roller as the curtain is wound upon and unwound from said elongated roller; and selectively operable drive means coacting with at least one extremity of said elongated roller for rotating said roller in either direction to wind said curtain on said elongated roller, or unwind it therefrom.

2. A closure apparatus in accordance with claim 1 wherein the flexible curtain is a heat sealable thermoplastic resin membrane.

3. A closure apparatus in accordance with claim I wherein the flexible curtain is a cord-reinforced thermoplastic resin membrane.

4. A closure apparatus in accordance with claim 3 wherein the cord is nylon cord.

5. A closure apparatus in accordance with claim 4 wherein the thermoplastic membrane is a poly(vinyl chloride) resin.

6. A closure apparatus in accordance with claim 1 wherein the flexible curtain includes reinforcing strips along each free, side marginal edge.

7. A closure apparatus in accordance with claim 1 wherein the curtain is under tension in a direction parallel to the axis of said elongated roller. 

1. A closure apparatus for an opening in a building structure, said opening being defined by a base, a head member and side members, comprising: a. an elongated roller of sufficient length to sag when supported in a horizontal position by its extremities only; b. means for securing the ends of the roller to said header adjacent the opening for rotation about its longitudinal axis; c. a flexible rectangular curtain dimensioned to cover the opening and secured along a marginal edge to said elongated roller and fabricated from:
 1. a plurality of panels of flexible material and rectangular configuration in coplanar side-by-side relation and having adjacently disposed marginal edges in confronting relation; and
 2. a separate narrow strip of flexible material similar to said panel material secured to each of adjacent panels in overlapping relation with marginal portions of each of said adjacent panels and coextensively overlying said confronting marginal edges; e. means for supporting the roller intermediate its extremities including at least one support roller disposed in load supporting relation with said elongated roller and curtain and having its axis of rotation parallel to the axis of rotation of said elongated roller, and a supporting bracket in which said support roller is mounted for rotation, said bracket being secured to said head member and disposed relative to said curtain so that said narrow strip of flexible material passes between said support roller and said elongated roller as the curtain is wound upon and unwound from said elongated roller; and f. selectively operable drive means coacting with at least one extremity of said elongated roller for rotating said roller in either direction to wind said curtain on said elongated roller, or unwind it therefrom.
 2. a separate narrow strip of flexible material similar to said panel material secured to each of adjacent panels in overlapping relation with marginal portions of each of said adjacent panels and coextensively overlying said confronting marginal edges; e. means for supporting the roller intermediate its extremities including at least one support roller disposed in load supporting relation with said elongated roller and curtain and having its axis of rotation parallel to the axis of rotation of said elongated roller, and a supporting bracket in which said support roller is mounted for rotation, said bracket being secured to said head member and disposed relative to said curtain so that said narrow strip of flexible material passes between said support roller and said elongated roller as the curtain is wound upon and unwound from said elongated roller; and f. selectively operable drive means coacting with at least one extremity of said elongated roller for rotating said roller in either direction to wind said curtain on said elongated roller, or unwind it therefrom.
 2. A closure apparatus in accordance with claim 1 wherein the flexible curtain Is a heat sealable thermoplastic resin membrane.
 3. A closure apparatus in accordance with claim 1 wherein the flexible curtain is a cord-reinforced thermoplastic resin membrane.
 4. A closure apparatus in accordance with claim 3 wherein the cord is nylon cord.
 5. A closure apparatus in accordance with claim 4 wherein the thermoplastic membrane is a poly(vinyl chloride) resin.
 6. A closure apparatus in accordance with claim 1 wherein the flexible curtain includes reinforcing strips along each free, side marginal edge.
 7. A closure apparatus in accordance with claim 1 wherein the curtain is under tension in a direction parallel to the axis of said elongated roller. 